Sound amplifier for radiocabinets



Feb. 4, 1930. J. w. SMALL SOUND AMPLIFIER FOR RADIOCABINETS Filed Feb. 6

UI hh. Ihn lull, 1| I Patented Feb. 4, 1930 PATENT OFFICE JAMES W. SMALL, OF CHICAGO, ILLINOIS SOUND AMPLIFIER FOR RADIOCABINETS Application led February 6, 1926. Serial No. 86,385.

This invention relates to sound amplifiers for radiolcabinets containing a radio receivf ing set or other reproducing instrument and has for its object the provision of an amplifier of the class mentioned which shall be of improved construction and operation which shall be conveniently arranged in the radio receiving set and which will develop improved acoustic properties.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawing and. described in the following specification, and it is more particularly pointed out vin the appended 15 claims.

In the drawing:

Fig. 1 is an end elevation of a radio cabinet with the end wall broken away showing one embodiment of the present invention;

Fig. 2 is a top plan view of the cabinet shown in F ig. 1 with parts broken away;

Fig. 3 is a front elevation of'the amplifying horn'forming :i part of the present invention;

Fig. 4 shows a modified form of amplifying horn; and

Fig. 5 is a fragmentary elevation of a detail of the support for the horn. The cabinet with which I prefer to com- 30 bine my improved amplifier comprises the compartment mounted on suitable supports 11, the compartment having a bottom 12, a rear wall 13, a front downwardly swinging door 14, and a top door whichA raises upwardly and`rearwardly. At the' top and front of the cabinet there is an inclined portion 16 made of suitableopen work to permit the passage of sound therethrough.

The inclined portion 16 may be covered with fabric, if desired. A partition wall 17 dividesthe bottom portion of the compartment 10 yinto front and rear sections. section 18 contains the radio receiving set 19. A removable cover 20 closes the top of the section 18 but may be lifted to permit access to the radio receiving set 19 without the necessity of disconecting the set and removing it through the opening closed'by the door 14. The space in the rear of the wall 17 may be utilized for housing the batteries 21 for The front operating the receiving set. Above the space occupied by the batteries and the receiving set, there is located an amplifying horn 22. rThis horn is shown inost clearly in Figs. 2 and 3, and is shaped to amplify the sound from the reproducer without distortion or interference so that all of the notes with their peculiar qualities and tone effects will be discernible in the amplified sound. The amplifying hon comprises a main compartment 50 23 having upright front and rear Walls 24 and 25, respectively, which are inclined to form a gradually tapering opening increasing from the right to the lefthand end of the horn, as viewed in Figs. 2 and 3. The 65 front and rear walls 24 and 25 may be made of Wood or other substance having suitable acoustic properties. The top of the compartment 23 is covered by a plate 26 of similar material and the bottom is closed by a sim 70 ilar plate 27.' Within the compartment is a second compartment 28 which has its larger end directed toward the smaller end of the compartment 23 and has its larger end open adjacent the smaller end of the compartment 23. The compartment 28 is formed by an upright plate 29 and a top plate 30 which co-operate with the side wall 24 and the bottom wall 27 of the main compartment to provide an open passage extending along one corner of the main compartment 23. The end of the compartment 23 adjacent the open end of the compartment 28 is rounded so that the sound escaping from thev compartment- 28 will be defiected toward the larger end of the compartment 23. An opening 31 is provided through the Wall 24 adjacent the smaller end of the compartment28 for receiving the sound conduit 32 of the sound reproducing element 33.

At the end of the chamber 23 opposite the open end of the compartment 28 there is an inclined upright wall 35 which reflects the sound waves toward the front of the cabinet and against an inclined Wall 36 at 95 one side of the exit portion of the amplifier. The cxitportion of the amplifier comprises the side wall 36, an opposite side wall 37. a cover portion 38` and a bottom portion 39. The side walls 36 and 37 are rearwardly in- 100 clined, as shown in Figure 1, to conform to the front Wall 16 of the sound cabinet. This exit portion of the amplifier is tapered so that the open mouth is the larger portion of the amplifying chamber. tion is also inclined toward the center of the cabinet. This not only brings the mouth of the horn closer to the center of the cabinet but ositions the wall 36 at the proper angle relative to the wall 85 to reflect the sound outwardly and to produce the desired tone effects. It should be noted that the passage for the sound is continually tapered from the opening 31 to the mouth of the discharged portion. The overlapping relation of the portions of the sound passage makes it possible to provide an elongated passage within a restricted space. It has been found by -tests that the particular shape and relation ofthe parts. as shown and described. not only permits the use of' a long horn within a small space but provides an amplifier in which the original tones are reproduced with remarkable faithfulness and claritv and in which clashing and interference is avoided.

The arrangement of' the battery within the saine compartment as the amplifying horn provides economy ot space and convenience of' operation and the position of the battery in the rear of the receiving set not onlv is economical in utilization ofthe space within the cabinet but avoids the use of extended leads and positions the parts so that theiv may be readily accessible.

rllhere are three principal characteristics of' the amplifvinfr horn that are believed to contribute chiefly to its improved acoustic properties. (lne of these features is the great length of the sound passage. The horn is provided Iwith two overlapping sound passages extending lengthwise of the cabinet which gives opportunity for increased length with a minimum number of bends. The secood feature is the fact that there are no right angle bends in the sound passage and no opportunity for direct reflection of the sound waves back upon themselves. This prevents blasting and destruction of minor tones. A 'third feature of value is the continuously increasing cross sectional area of the tone passage.

In Figs. 1. Q and 3 the amplifying horn is shown as supported on rigid Wooden arms. Instead of these arms. flexible straps 41 may be employed. These straps may be provided with openings 42 for removably engaging supporting pins on the inside walls of the cabinet. The flexible members 41 provide a floating support for the horn which frees it from external disturbances and permits it to respond more readily to the sound vibrations transmitted through it.

I claim 1. In asound amplifier for radio appa- The exit por-v ratus, a cabinet, an elongated horn-like casing in said cabinet, flexible members secured to said casing and to said cabinet for supporting said amplifier, said casing being partitioned off into communicating horizontal tapered passages with sound deflectors at the ends of said passages, said passages being tapered from the sound reproducing connection with the radio apparatus to the eXit portion of the casing, and said exit portion being disposed at an abrupt angle to the longitudinal partition in the horn-like casing.

Q. A sound amplifier for radio apparatus, comprising a cabinet7 an elongated horn-like casing in said cabinet` flexible members secured at one end to said casing and adapted to be secured to said cabinet at their opposite ends for supporting the amplifier, said casing being partitioned off' into communieating horizontal tapered passages with sound deflectors at the ends of said passages, said passages being tapered from the sound reproducing connection with the radio apparatus to the exit portion of the casing, and said exit portion of the casing being disposed at an abrupt angle to the longitudinal partitions in the horn-like casing and having rearwardly inclined side Walls providing a forwardly extending bottom and a relatively short top. I

3. In a sound amplifier for radio apparatus. a supporting structure` a sound amplifving tone chamber, a reproducing unit carried bv said tone chamber and Wholly supported thereby during the reproducing action of said unit. and flexible members for suspending said tone chamber and unit from said supporting structure.

4. In a sound amplifier for radio apparatus, a supporting structure. a sound amplifying tone chamber. a reproducing unit carried by said tone chamber and Wholly supported thereby during the reproducing action of said unit, and a floating support for said tone chamber and reproducing unit.

In testimony whereof I have signed my name to this specification on this 4th day of February, A. D. 1926.

JAMES W. SMALL. 

